High- and Low-Mass Star Forming Regions from Hierarchical Gravitational Fragmentation. High local Star Formation Rates with Low Global Efficiencies

Abstract

We investigate the properties of "star forming regions" in a previously published numerical simulation of molecular cloud formation out of compressive motions in the warm neutral atomic interstellar medium, neglecting magnetic fields and stellar feedback. In this simulation, the velocity dispersions at all scales are caused primarily by infall motions rather than by random turbulence. We study the properties (density, total gas+stars mass, stellar mass, velocity dispersion, and star formation rate) of the cloud hosting the first local, isolated "star formation" event in the simulation and compare them with those of the cloud formed by a later central, global collapse event. We suggest that the small-scale, isolated collapse may be representative of low- to intermediate-mass star-forming regions, while the large-scale, massive one may be representative of massive star forming regions. We also find that the statistical distributions of physical properties of the dense cores in the region of massive collapse compare very well with those from a recent survey of the massive star forming region in the Cygnus X molecular cloud. The star formation efficiency per free-fall time (SFE_ff) of the high-mass SF clump is low, ~0.04. This occurs because the clump is accreting mass at a high rate, not because its specific SFR (SSFR) is low. This implies that a low value of the SFE_ff does not necessarily imply a low SSFR, but may rather indicate a large gas accretion rate. We suggest that a globally low SSFR at the GMC level can be attained even if local star forming sites have much larger values of the SSFR if star formation is a spatially intermittent process, so that most of the mass in a GMC is not participating of the SF process at any given time.

Accepted by ApJ. Revised version, according to exchanges with referee. Original results unchanged. Extensive new discussion on the low global efficiency vs. high local efficiency of star formation. Abstract abridged

References in corpus (18)

• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• Slow Star Formation in Dense Gas: Evidence and Implications
• The Density Probability Distribution in Compressible Isothermal Turbulence: Solenoidal versus Compressive Forcing
• Molecular Cloud Evolution II. From cloud formation to the early stages of star formation in decaying conditions
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• Star formation in Perseus - V. Outflows detected by HARP
• The Large and Small Scale Structures of Dust in the Star-Forming Perseus Molecular Cloud
• On the Rapid Collapse and Evolution of Molecular Clouds
• The Birth of Molecular Clouds: Formation of Atomic Precursors in Colliding Flows
• The Global Evolution of Giant Molecular Clouds. I: Model Formulation and Quasi-Equilibrium Behavior
• Cooling, Gravity and Geometry: Flow-driven Massive Core Formation
• On the Structure of the Orion A Cloud and the Formation of the Orion Nebula Cluster
• Kinematics of the Orion Nebula Cluster: Velocity Substructure and Spectroscopic Binaries
• A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
• The effect of stellar winds on the formation of a protocluster
• Probing the formation of intermediate- to high-mass stars in protoclusters II. Comparison between millimeter interferometric observations of NGC 2264-C and SPH simulations of a collapsing clump
• Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N
• Properties of Stellar Clusters around High-Mass Young Stars

Cited by in corpus (103)

• High-Mass Star and Massive Cluster Formation in the Milky Way
• The Star Formation Rate and Gas Surface Density Relation in the Milky Way: Implications for Extragalactic Studies
• Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
• Dynamic star formation in the massive DR21 filament
• Cluster-formation in the Rosette molecular cloud at the junctions of filaments
• Maximally Star-Forming Galactic Disks I. Starburst Regulation Via Feedback-Driven Turbulence
• Accretion-Driven Turbulence as Universal Process: Galaxies, Molecular Clouds, and Protostellar Disks
• The ALMA Survey of 70 $\mu$m dark High-mass clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation
• Limiting Accretion onto Massive Stars by Fragmentation-Induced Starvation
• Gravity or turbulence? II. Evolving column density PDFs in molecular clouds
• Partially Ionized Plasmas in Astrophysics
• Filaments in Simulations of Molecular Cloud Formation
• How long does it take to form a molecular cloud?
• The Physics of Star Cluster Formation and Evolution
• Molecular Cloud Evolution III. Accretion vs. stellar feedback
• Gravity drives the evolution of infrared dark hubs: JVLA observations of SDC13
• Gravity or turbulence? -III. Evidence of pure thermal Jeans fragmentation at ~0.1 pc scale
• Filamentary Fragmentation and Accretion in High-Mass Star-Forming Molecular Clouds
• From the Convergence of Filaments to Disk-Outflow Accretion: Massive-Star Formation in W33A
• The Bolocam Galactic Plane Survey. XIV. Physical Properties of Massive Starless and Star Forming Clumps
• Filamentary Accretion Flows in the Infrared Dark Cloud G14.225-0.506 Revealed by ALMA
• Molecular Cloud Evolution V. Cloud Destruction by Stellar Feedback
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XI. From inflow to infall in hub-filament systems
• An Evolutionary Model for Collapsing Molecular Clouds and Their Star Formation Activity
• MUSCLE W49 : A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. Data and The Mass Structure of the Giant Molecular Cloud
• The rate and latency of star formation in dense, massive clumps in the Milky Way
• The Spatial Distribution of the Young Stellar Clusters in the Star Forming Galaxy NGC 628
• Investigating the structure and fragmentation of a highly filamentary IRDC
• Unbound Young Stellar Systems: Star Formation on the loose
• On column density thresholds and the star formation rate
• Hierarchical Star Formation in Nearby LEGUS Galaxies
• Time Varying Dynamical Star Formation Rate
• Massive 70 micron quiet clumps II: non-thermal motions driven by gravity in massive star formation?
• Cloud Structure of Galactic OB Cluster Forming Regions from Combining Ground and Space Based Bolometric Observations
• Hierarchical Star Formation in Turbulent Media: Evidence from Young Star Clusters
• An Evolutionary Model for Collapsing Molecular Clouds and Their Star Formation Activity. II. Mass Dependence of the Star Formation Rate
• Scale-free gravitational collapse as the origin of $\rho \sim r^{-2}$ density profile -- a possible role of turbulence in regulating gravitational collapse
• The Dependence of Star Formation Efficiency on Gas Surface Density
• Collapse of turbulent massive cores with ambipolar diffusion and hybrid radiative transfer I. Accretion and multiplicity
• Feedback from OB stars on their parent cloud: Gas exhaustion rather than gas ejection
• Cloud structure of three Galactic infrared dark star-forming regions from combining ground and space based bolometric observations
• Feeding vs. Falling: The growth and collapse of molecular clouds in a turbulent interstellar medium
• A diversity of starburst-triggering mechanisms in interacting galaxies and their signatures in CO emission
• Rapid Circumstellar Disk Evolution and an Accelerating Star Formation Rate in the Infrared Dark Cloud M17 SWex
• The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores
• On the shape and completeness of the column density probability distribution function of molecular clouds
• Hierarchical Stellar Structures in the Local Group Dwarf Galaxy NGC 6822
• Energy budget of forming clumps in numerical simulations of collapsing clouds
• Star Formation in Molecular Clouds
• The effect of photoionising feedback on the shaping of hierarchically-forming stellar clusters
• Structure and Expansion Law of HII Regions in structured Molecular Clouds
• New insights in the HII region G18.88-0.49: hub-filament system and accreting filaments
• Multi-scale dynamics in star-forming regions: the interplay between gravity and turbulence
• Multi-scale analysis of the Monoceros OB 1 star-forming region: II. Colliding filaments in the Monoceros OB1 molecular cloud
• High-resolution APEX/LAsMA ${}^{12}$CO and ${}^{13}$CO (3-2) observation of the G333 giant molecular cloud complex : I. Evidence for gravitational acceleration in hub-filament systems
• Collapse of turbulent massive cores with ambipolar diffusion and hybrid radiative transfer II. Outflows
• Star formation in the filament of S254-S258 OB complex: a cluster in the process of making
• The Small-Scale Physical Structure and Fragmentation Difference of Two Embedded Intermediate Mass Protostars in Orion
• Molecular Cloud Evolution VI. Measuring cloud ages
• GASTON: Galactic Star Formation with NIKA2. Evidence for the mass growth of star-forming clumps
• Interstellar MHD Turbulence and Star Formation
• The Effects of Inhomogeneities within Colliding Flows on the Formation and Evolution of Molecular Clouds
• Formation of the SDC13 Hub-Filament System: A Cloud-Cloud Collision Imprinted on The Multiscale Magnetic Field
• Simultaneous evolution of the virial parameter and star formation rate in molecular clumps undergoing global hierarchical collapse
• The Dependence of the Hierarchical Distribution of Star Clusters on Galactic Environment
• Galactic Cold Cores. VIII. Filament formation and evolution: Filament properties in context with evolutionary models
• Unveiling the formation of the massive DR21 ridge
• Mid-J CO shock tracing observations of infrared dark clouds II Low-J CO constraints on excitation, depletion, and kinematics
• Unraveling the observational signatures of cloud-cloud collision and hub-filament systems in W31
• Understanding formation of young, distributed low-mass stars and clusters in the W4 cloud complex
• The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE: Overview and first results toward DR20 from the Max Planck IRAM Observatory program (MIOP)
• Molecular cloud formation as seen in synthetic Hi and molecular gas observations
• Multi-scale analysis of the Monoceros OB 1 star-forming region: I. The dense core population
• Formation of Massive Star Clusters by Fast HI Gas Collision
• Unveiling the importance of magnetic fields in the evolution of dense clumps formed at the waist of bipolar H II regions: a case study on Sh2-201 with JCMT SCUBA-2/POL-2
• The Duration of Star Formation in Galactic Giant Molecular Clouds. I. The Great Nebula in Carina
• Formation of hub-filament structure triggered by cloud-cloud collision in W33 complex
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- VI. On the formation of the "L" type filament in G286.21+0.17
• Star Formation in Massive Clusters via Bondi Accretion
• Evolution of the angular momentum during gravitational fragmentation of molecular clouds
• Dependence of the Star Formation Efficiency on the Parameters of Molecular Cloud Formation Simulations
• High-resolution APEX/LAsMA ${}^{12}$CO and ${}^{13}$CO (3-2) observation of the G333 giant molecular cloud complex : II. Survival and gravitational collapse of dense gas structures under feedback
• The disk-outflow system around the rare young O-type protostar W42-MME
• Kinematics and chemistry of the hot core in G20.08-0.14N
• New evidences in IRDC G333.73+0.37: colliding filamentary clouds, hub-filament system, and embedded cores
• Simulated observations of star formation regions: infrared evolution of globally collapsing clouds
• Unraveling the inner substructure of new candidate hub-filament system in the HII region G25.4NW
• Filamentary Structures and Star Formation Activities in the Sites S234, V582, and IRAS 05231+3512
• Probing the initial conditions of high-mass star formation. III. Fragmentation and triggered star formation
• Star-forming site RAFGL 5085: Is a perfect candidate of hub-filament system ?
• The kinetic and magnetic energy budget of hub-filament systems during the gravitational fragmentation of molecular clouds
• Testing assumptions and predictions of star-formation theories
• Linking High- and Low-Mass Star Formation: Observation-Based Continuum Modelling and Physical Conditions
• Probing the Global Dust Properties and Cluster Formation Potential of the Giant Molecular Cloud G148.24+00.41
• ALMA observations of two massive and dense MALT90 clumps
• Searching for converging flows of atomic gas onto a molecular cloud
• Filamentary Hierarchies and Superbubbles I: Characterizing filament properties across a simulated spiral galaxy
• Turbulence and its connection to episodic accretion in binary YSOs
• Virial Ratio: Direct Evaluation from Molecular Cloud Data and the Challenges of Improving Accuracy
• Gravity or turbulence? VII. The Schmidt-Kennicutt law, the star formation efficiency, and the mass density of clusters from gravitational collapse rather than turbulent support
• Gravity as the main driver of non-thermal motions in massive star formation
• Theory of Feedback in Clusters and Molecular Cloud Turbulence
• Cluster Assembly in Hierarchically Collapsing Clouds